Liquid crystal display device having black and transparent spacers in the transmissive region

ABSTRACT

In a semi-transmissive liquid crystal display device provided with a liquid crystal panel DP and a backlight BL, black spacers and transparent spacers are mixed and provided in a space between two opposing transparent substrates  4   a  and  4   b , and let r be a radius of the spacers and S be a dimension of a light transmissive region T in a single pixel, then a value of πr 2 /S is set in a range from 0.001 to 0.01. A stable display is thus enabled by eliminating display irregularities.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semi-transmissive liquid crystaldisplay device having a light reflective region and a light transmissiveregion in a single pixel region, and more particularly, to the structureof a spacer that defines an interval between a pair of top and bottomsubstrates.

2. Description of Related Art

In recent years, a liquid crystal display device has been usedextensively as a large-scale, high-definition monitor besides a small-or medium-scale personal digital assistant and a notebook computer.

A display mode of the liquid crystal display device includes areflective mode in which display is performed using external light thatcomes incident on the display surface, a transmissive mode in which abacklight is used and display is performed by allowing light from thebacklight to pass through the display surface, and a semi-transmissivemode furnished with the functions of both modes.

A semi-transmissive liquid crystal display device achieving thesemi-transmissive mode is used as a reflective device with the use ofexternal illumination, such as sunlight or fluorescent light, or is usedas a transmissive device by attaching a backlight. In order to providethe display functions of both types, it uses a semi-transmissive film(structured to serve as a half mirror by laminating plural dielectricfilms having different refractive indexes alternately).

When such a semi-transmissive film serving as a half mirror is used, itis difficult to enhance both functions of reflectance and transmittance.

In order to solve this problem, a semi-transmissive liquid crystaldisplay device is assembled by forming a reflection film in a pixelregion and providing a light transmission hole (light transmissiveregion) in part of the reflection film formed in the pixel region forallowing light from the backlight to pass through.

Meanwhile, it is quite important for the liquid crystal display deviceto keep a liquid crystal layer uniform at a thickness of a specificvalue. Hence, in general, a number of fine, transparent spacers to keepthe liquid crystal layer at a uniformed thickness are mixed in theliquid crystal layer.

For this reason, in a semi-transmissive liquid crystal device, forexample, when black is displayed in a transmissive mode (a display statewhere transmitted light is shielded), white dropouts readily occur dueto the transparent spacers per se and an alignment defect of the liquidcrystal on the periphery of the spacers. This is because while liquidcrystal molecules are in a twisted state in a space between twosubstrates, those on the periphery of the spacers go into a state wherethey apparently stand perpendicularly in the space between the twosubstrates, and the twisted state of the liquid crystal molecules on theperiphery of the spacers is thereby disturbed, which gives rise to alight leaking phenomenon in the liquid crystal layer near the spacersurface.

In addition, spacers provided in a space between two substrates aretransparent, and provided on a random basis by means of wet scatteringor dry scattering. Hence, the number of spacers provided above the lighttransmission hole is not constant.

Because a degree of white dropouts in each pixel depends on the numberof spacers provided above the light transmission hole, white dropoutportions across the entire display region appear as irregularities.

It is possible to prevent the white dropouts caused by a defect ofliquid crystal alignment as described above by using spacers(hydrophilic spacers) having undergone treatment to form alkyl groups onthe spacer surface. However, because only part of the pixel contributesto a transmissive display in the transmissive mode, the size of thepixel becomes relatively small with respect to the size of the spacers.Hence, when white is displayed on the contrary (a display state wheretransmitted light is allowed to pass through), black irregularities, bycontrast, appear across the entire display region when an alignmentrestraining force is too strong.

In the semi-transmissive liquid crystal display device having both thelight reflective region and the light transmissive region in the pixelregion, display irregularities occur after all either in the blackdisplay or in the white display.

When the liquid crystal display device is formed using the hydrophilicspacers, leakage of light from the periphery of the spacers can beprevented. However, there arises another problem that an alignmentdefect of liquid crystal molecules occurs between close spacers.

In order to keep the liquid crystal layer uniform, the necessary mixingdensity of spacers is 80 or more pieces per 1 mm² when viewed in aplane, and in order to maintain the liquid crystal layer in a stablemanner, a density of 200 pieces per 1 mm² is necessary. However, whenhydrophilic spacers are mixed at a high density, an alignment defect ofliquid crystal molecules between spacers becomes noticeable.

FIG. 6 is a plan view of pixel regions showing an inconvenience causedby a defective liquid crystal alignment between hydrophilic spacers.

Hydrophilic spacers 10 a are provided in the respective pixel regions.The base material of the spacers is formed by subjecting a monomerhaving unsaturated ethylene groups to suspension polymerization using aradical polymerizing agent. Polymerization treatment to polymerize alkylgroups (having about 12 carbons) on the surface of the base material ofthe spacers is applied as hydrophilic treatment.

As a consequence, when the spacers 10 a to surfaces of which is appliedhydrophilic treatment are provided, because a restraining force to alignliquid crystal is exerted on the surface of each spacer 10 a, a linearalignment defect region having close spacers as a nucleus as is denotedby numeral 15 may possibly occur due to an external force or stress,such as heat, in a portion where spacers are close to each other.Because there is no phase difference in this linear alignment defectregion 15, it becomes a luminous spot in the black display.

Conversely, when a scattering density of spacers is reduced to controlthe linear alignment defects, the thickness of the liquid crystal layerbecomes less uniform. The liquid crystal molecules in the liquid crystallayer then become unable to move stably, which results in a problem thatliquid crystal display is disturbed.

An object of the invention is to provide a semi-transmissive liquidcrystal display device using a reflection film provided with lighttransmission holes that is capable of performing a stable display byeliminating display irregularities caused by spacers mixed in the liquidcrystal layer.

An object of the invention is to provide a liquid crystal display devicecapable of performing a stable display while suppressing linearalignment defects having spacers as a nucleus that occur between closespacers.

SUMMARY OF THE INVENTION

A liquid crystal display device of the invention includes: a firstsubstrate, on a display surface side, provided with a transparentconducting film and an alignment film; a second substrate disposedoppositely to the first substrate on a back surface side and providedwith a transparent conducting film and an alignment film; a liquidcrystal layer filled in a space between the two substrates; a reflectionfilm provided on the second substrate; plural spacers provided in theliquid crystal layer; and a backlight that supplies light to the pixelregions via the second substrate. The reflection film has a lightreflective region and a light transmissive region provided with a lighttransmission hole for each pixel region, and light transmittance of theplural spacers provided in the light transmissive region is in a rangefrom 20 to 80%.

According to this configuration, it is possible to achieve a highlystable liquid crystal display device having an excellent spacerscattering property and capable of effectively preventing white dropoutsin the black display, black dropouts in the white display, and adefective alignment of liquid crystal molecules caused by pressingparticularly in the light transmissive region, while achieving highvisual recognition without causing any display irregularity.

Also, a liquid crystal display device of the invention includes: a firstsubstrate, on a display surface side, provided with a transparentconducting film and an alignment film; a second substrate disposedoppositely to the first substrate on a back surface side and providedwith a transparent conducting film and an alignment film; a liquidcrystal layer filled in a space between the two substrates; a reflectionfilm provided on the second substrate; plural spacers provided on theliquid crystal layer; and a backlight that supplies light to the pixelregions via the second substrate. The reflection film has a lightreflective region and a light transmissive region provided with a lighttransmission hole for each pixel region. Let r be a radius of thespacers and S be an area of the light transmissive region, and thenπr²/S is set in a range from 0.001 to 0.01. Thus, white dropout portionsacross the entire display region will not appear as irregularities inthe black display in the transmissive mode, which improves visualrecognition. In addition, because the black spacers are not noticeablein the light transmissive region, it is possible to maintain a displayat high visual recognition.

Black spacers and transparent spacers are included, and a mixing ratiothereof is set in a range from 20:80 to 80:20. In this case,semi-transparent spacers may be further included. When configured inthis manner, the liquid crystal display device has no roughness in thewhite display, no roughness in the black display, and no irregularitiesof spacers in the color display.

The spacers may be formed of semi-transparent spacers.

Part of or all the black spacers may be spacers subjected to hydrophilictreatment, each being made of a black base material particle and ahydrophilic group film deposited on a surface of the particle. Becausethe hydrophilic group film is deposited on the surface of the black basematerial particle, a scattering property of the spacers is increasedregardless of the absence or presence of the alkyl group film on theperiphery. This not only prevents aggregation of the spacers in thedisplay region, but also enables visual recognition to be maintainedhigh.

Further, it is preferable that an alkyl group film having up to 11 to 13carbons is formed and deposited on a surface of the hydrophilic groupfilm. By forming the alkyl group film on the spacer surface, it ispossible to prevent an event that alkyl groups formed on the surface ofthe spacer align liquid crystal molecules with their apparent cilia(needle-like cilia formed apparently on the spacer surface), whichcauses the liquid crystal molecules to be lined up to stand on theperiphery of the spacer. This can prevent leakage of light from theperiphery of the spacer.

In addition, a liquid crystal display device of the invention includes:a first substrate, on a display surface side, provided with atransparent conducting film and an alignment film; a second substratedisposed oppositely to the first substrate on a back surface side andprovided with a transparent conducting film and an alignment film; aliquid crystal layer filled in a space between the two substrates; areflection film provided on the second substrate; plural spacersprovided on the liquid crystal layer; and a backlight that supplieslight to the pixel regions via the second substrate. The plural spacersinclude spacers to surfaces of which is applied hydrophobic treatmentand spacers to surfaces of which is applied hydrophilic treatment.

By mixing spacers to surfaces of which is applied hydrophobic treatmentand spacers to surfaces of which is applied hydrophilic treatment, andproviding the mixed spacers to the liquid crystal layer, a ratio of thespacers having undergone hydrophilic treatment can be reduced withrespect to a total quantity of the spacers. Hence, not only is itpossible to suppress a linear alignment defect between the spacerseffectively, but it is also possible to maintain a density of thespacers to a specific value or above at the same time. This enables thethickness of the liquid crystal layer to be maintained uniformly in astable manner.

It is preferable to set a mixing ratio of the spacers to surfaces ofwhich is applied hydrophobic treatment and the spacers to surfaces ofwhich is applied hydrophilic treatment in a range from 20:80 to 80:20.

The above and other objects, features, and advantages of the inventionwill become more apparent from the following description of embodimentswith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross section of a liquid crystal display deviceof the invention;

FIG. 2 is a schematic plan view showing the structure of a reflectionfilm used in the liquid crystal display device of the invention;

FIG. 3A is a plan view of pixel portions in the absence of localizationof spacers;

FIG. 3B is a plan view showing pixel portions in the presence oflocalization of spacers;

FIG. 4 is a view showing the structure of a spacer used in theinvention;

FIG. 5 is a plan view showing a state where two kinds of spacers(hydrophilic spacers and hydrophobic spacers) are provided in pixelportions of the liquid crystal display device of the invention; and

FIG. 6 is a plan view showing a state of a defective alignment caused byone kind of spacers (hydrophilic spacers) in pixel portions of a liquidcrystal display device in the related art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a cross section schematically showing the structure of aliquid crystal display device of the invention. FIG. 2 is a plan viewdescribing the structure of pixel regions on a bottom substrate. FIG. 3is a schematic view describing spacers scattered in liquid crystal.

The liquid crystal display device comprises a liquid crystal displaypanel DP and a backlight BL.

The backlight BL is disposed on the outside of a transparent substrate 4b on the lower side of the liquid crystal display panel DP. Lighttherefrom passes through the liquid crystal layer by passing throughlight transmissive regions provided in the pixel regions, and reachesthe display surface of the liquid crystal display panel DP.

The liquid crystal display panel DP chiefly comprises a glass substrate4 a, which is a transparent substrate on the upper side, a glasssubstrate 4 b, which is a substrate on the lower side, and liquidcrystal 16 interposed therebetween.

Transparent electrodes 5 a made of ITO (indium tin oxide), SnO₂ (tinoxide) or the like, and an alignment film 6 a made of polyimide resin orthe like are deposited in this order on the inner main surface of theglass substrate 4 a, which is the transparent substrate on the upperside.

A reflection film 9, a color filter 8, a smoothing film 7, transparentelectrodes 5 b, and an alignment film 6 b are deposited in this order onthe inner main surface of the glass substrate 4 b, which is thetransparent substrate on the lower side.

The transparent electrodes 5 a on the top substrate 4 a extend in adepth direction of the sheet surface of FIG. 1, and plural of them areformed in stripes to be parallel to each other. Also, regarding thetransparent electrodes 5 b on the bottom substrate 4 b, plural of themare formed in stripes to be parallel to each other in a crosswisedirection of the sheet surface of FIG. 1.

Hence, when viewed in a plane from the display surface side, thetransparent electrodes 5 a and the transparent electrodes 5 b cross eachother, and these crossing portions form “pixel regions”. The pixelregions are arrayed laterally and longitudinally so as to form “adisplay region”.

Because the liquid crystal display device of this embodiment is a colorliquid crystal display device provided with the color filter 8, eitherone of three kinds of filters (red (R), green (G), and blue (B)) thattogether form the color filter 8 is deposited on a single pixel region.

In addition, the alignment film 6 a to control the alignment of liquidcrystal molecules of the liquid crystal 16 is formed on the transparentelectrodes 5 a, and the alignment film 6 b to control the alignment ofliquid crystal molecules of the liquid crystal 16 is also formed on thetransparent electrode 5 b. These alignment films 6 a and 6 b are madeof, for example, polyimide resin, and after they are applied and curedthey are subjected to rubbing treatment in a specific direction. Aninsulation film made of resin, SiO₂ or the like may be interposedbetween, respectively, the transparent electrodes 5 a and 5 b and thealignment films 6 a and 6 b.

Further, as has been described above, the reflection film 9 made ofmetal, the color filter 8, the smoothing film 7 made of acrylic resin toserve as an overcoat are formed between the inner main surface of thebottom substrate 4 b and the transparent electrodes 5 b.

The reflection film 9 has light transmission holes in the respectivepixel regions where part of the reflection film 9 is removed. The lighttransmission holes are referred to as “light transmissive regions T”.Also, regions in the respective pixel regions where the reflection film9 is left serve as “light reflective regions R”. It should be noted thatthe reflection film 9 is present also in boundary portions (hereinafterreferred to as “inter-pixel regions”) between adjacent pixel regions.

The color filter 8 is formed by applying photosensitive resist, preparedby dispersing a pigment (one of red, green, and blue) in a resinmaterial, onto a specific region in the pixel region, followed bypatterning by means of photolithography and curing.

A resin film containing a black pigment may be formed in the inter-pixelregions. The black resin film is formed in a matrix fashion or instripes to surround the respective pixel regions.

Although it is not shown in the drawing, one size larger sealingportions than the display region are formed on the substrates 4 a and 4b, and the substrate 4 a and the substrate 4 b are laminated to eachother using these sealing portions, after which the liquid crystal 16 issealed in a space therebetween.

The liquid crystal 16 is, for example, a twisted, chiral nematic liquidcrystal material. When no electric field is applied between thetransparent electrodes 5 a and 5 b under the alignment control by thealignment films 6 a and 6 b that come into contact with the liquidcrystal 16, liquid crystal molecules are arrayed helically, for example,at an angle of 200° to 260°. When an electric field is applied betweenthe transparent electrodes 5 a and 5 b, the helical array is broughtinto line. Light passing through the liquid crystal 16 is polarized withthese two states.

Also, a number of spacers 10 are scattered inside the liquid crystal 16to keep the thickness of the liquid crystal 16 constant. The spacers 10are of an ellipsoidal shape in FIG. 1 for ease of illustration. However,they are actually of a spherical shape.

In addition, a first phase difference plate 3 and a second phasedifference plate 2 made of polycarbonate or the like, and aniodine-based polarizing plate 1 are formed successively on the outermain surface of the surface substrate 4 a. A phase difference plate 11made of polycarbonate or the like and an iodine-based polarizing plate12 are formed successively on the outer main surface of the back surfacesubstrate 4 b. These plates are bonded to each other via a bonding layermade of an acrylic material. A light-scattering film or the like may beprovided in addition to these phase difference plates and polarizingplates.

The backlight BL comprises an optical waveguide 17 having a main surfaceof a size comparable to that of the display region, and a light source18 disposed on the end face of the optical waveguide 17. Thesecomponents are disposed on the back surface side of the liquid crystaldisplay panel DP by means of a frame to establish specific positionalrelations with each other, so that the optical waveguide 17 correspondsto the display region of the liquid crystal panel DP.

In the liquid crystal display device of the structure as describedabove, when the pixel regions are concerned, as is shown in FIG. 2, asingle pixel region includes the light reflective region R and the lighttransmissive region T. A light-shielding portion 20 comprising the blackresin film is formed on the periphery of each pixel region. To cite anexample of numerical values, one pixel is formed to be 240 μm×320 μmacross the entire display region. The net outside dimensions a and b ofthe light reflective region R, excluding the width of thelight-shielding portion 20 from a single pixel, are: a=70 μm and b=230μm.

The reflection film 9 made of reflective metal is formed on the pixelregion, and the reflection film 9 is made of AlNd or the like and has athickness of about 1200 Å. Other available materials include Al, Alalloy (AlTi, etc.), Ag, Ag alloy (AgPd, AgPdCu, AgCuAu, etc.), and thethickness is set in a range from 1000 to 1500 Å.

The sizes c and d of the light transmissive region T formed in thereflection film 9 are, for example, c=50 μm and d=96.6 μm. Hence, aratio of the area of the light reflective region R to the area of thelight transmissive region T is R:T=70:30.

Because a single pixel region includes the light reflective region R andthe light transmissive region T as described above, in a display statein the reflective mode using external light that comes incident on thedisplay surface, a specific display is performed as light reaching thereflection film 9 from the display surface side via the liquid crystal16 is reflected on the reflection film 9 and exits from the displaysurface side again via the liquid crystal 16. In a display state in thetransmissive mode using light from the backlight BL, a specific displayis performed as light from the backlight passes through the lighttransmissive region T and exits from the display surface side via theliquid crystal 16.

The structure of the spacers 10 scattered in the liquid crystal layer 16to be provided without causing localization in the light reflectiveregion or the light transmissive region of the pixel will now bedescribed.

The spacers 10 include substantially transparent spacers, substantiallyblack spacers, and semi-transparent spacers.

The base material of the transparent spacers is formed by subjecting amonomer having unsaturated ethylene groups to suspension polymerizationusing a radical polymerizing agent. Transparent spacers provided in thelight transmissive regions referred to herein are those having lighttransmittance exceeding 80%.

The black spacers are obtained by mixing the monomer with a blackpigment or covering the periphery of the transparent base material witha black coating film. Black spacers provided in the light transmissiveregions referred to herein are those having light transmittance lessthan 20%.

The semi-transparent spacers 10 are formed by subjecting a monomerhaving unsaturated ethylene groups to suspension polymerization using aradical polymerizing agent. For the semi-transparent spacers provided inthe light transmissive regions to have light transmittance of 20 to 80%,the monomer is mixed with a small quantity of black pigment or theperiphery of the transparent base material is covered with a thin blackcoating film.

FIG. 3A and FIG. 3B are plan views showing spacers present in the lighttransmissive regions T.

FIG. 3A shows a state where the spacers are scattered evenly in theliquid crystal layer 16 and no display irregularities are present.

On the contrary, the spacers are scattered unevenly in the liquidcrystal layer 16 of FIG. 3B, and a degree at which light passing throughthe light transmissive region T is shielded by the spacers varies frompixel to pixel, which appears as display irregularities.

In other words, irregularities are generated by a difference of thenumbers of spacers in close pixels, in particular, spacers present inthe light transmissive regions T.

Let r be a radius of spacers (a radius of a particle forming the basematerial of the spacer) and S be the area of the light transmissiveregion T within a single pixel.

Then, given N as the number of spacers present in the light transmissiveregion T, the area ratio of the spacers in the light transmissive regionT is Nπr²/S.

Let NA and NB be the number of spacers present in two adjacent lighttransmissive regions TA and TB, respectively. Then, the area ratios ofthe spacers in the light transmissive regions TA and TB are NAπr²/S andNBπr²/S, respectively. A difference is:(NA−NB)πr ² /S  (1)and irregularities become more noticeable as the value increases. Hence,the value becomes smaller and irregularities become less noticeable as adifference between NA and NB becomes smaller and as the areas S of thelight transmissive regions are increased.

Another embodiment used in the invention will now be described withreference to FIG. 4.

In this embodiment, a spacer 10 comprises a black base material particle20 a and a hydrophilic group film 20 b deposited on the surface of theblack base material particle 20 a.

More preferably, an alkyl group film 20 c having up to 11 to 13 carbonsis deposited on the surface of the hydrophilic group film 20 b.

Referring to FIG. 4, the alkyl group film 20 c is illustratedschematically in the form of molecules. However, it is actually formedacross the entire surface of the hydrophilic group film 20 b, and thealkyl group film 20 c is in the form of a film.

The black base material particle 20 a used as the base material of theparticle can be produced through two methods.

One is a method in which a transparent spacer, formed by subjecting amonomer having unsaturated ethylene groups to suspension polymerizationusing a radical polymerizing agent, is used as the base, and the surfacethereof is covered with a black coating film, so that the black basematerial particle 20 a is formed as a whole.

The other is a method in which the monomer is mixed with a blackpigment, so that the base material itself is made in black.

A substitutional group film (referred to as hydrophilic group film) 20 bhaving a hydrophilic property is formed on the surface of the black basematerial particle 20 a produced in this manner, in a thickness of about0.05 μm. The purpose is to prevent aggregation during wet scattering.

More preferably, the alkyl group film 20 c is formed on the surface ofthe hydrophilic group film 20 b. Because external light and light fromthe backlight on the periphery of the spacer 10 pass through regardlessof whether the display is ON or OFF, the alkyl group film 20 celiminates passing of light by controlling the alignment control on theliquid crystal molecules of the liquid crystal 16.

The film thicknesses of the hydrophilic group film and the alkyl groupfilm included in the radius of the spacer are negligibly small. Hence,the radius of the spacer can be actually the radius of the base materialparticle.

Still another embodiment will now be described with reference to FIG. 5and FIG. 6.

In this embodiment, spacers 10 include hydrophilic spacers 10 a andhydrophobic spacers 10 b.

FIG. 5 is a plan view showing three adjacent pixel regions. Referring toFIG. 5, transparent or semi-transparent spacers 10 are provided in thepixel regions (regions enclosed by the black resin 20). The basematerial of the spacers 10 is formed by subjecting a monomer havingunsaturated ethylene groups to suspension polymerization using a radicalpolymerizing agent.

Of these spacers 10, the spacers 10 a having undergone hydrophilictreatment are spacers formed by applying polymerization treatment topolymerize alkyl group (having about 12 carbons) to the surface of thespacer base material.

The hydrophobic spacers 10 b are spacers to which the alkyl grouptreatment as described above is not applied. In other words, thehydrophobic spacers 10 b use the spacer base material simplexes (theyshow a hydrophobic property when the surface is not treated).

Firstly, in a case where only the spacers 10 a to the surfaces of whichis applied hydrophilic treatment are used as the spacers 10, forexample, a linear alignment defect region 15 having spacers 10 a as anucleus may possibly occur between the spacers 10 a and 10 a as is shownin FIG. 6 due to an external force or stress, such as heat, in a portionwhere the spacers 10 a are close to each other, because a strongrestraining force to align the liquid crystal is exerted on the surfaceof each spacer 10 a. Because light has no phase difference in thislinear alignment defect region 15, it becomes a luminous spot in theblack display.

Secondly, in a case only the hydrophobic spacers 10 b are provided, theliquid crystal in the liquid crystal layer 3 tends to be arrayeddepending on the outside shape of the hydrophobic spacers 10 b in aportion where the hydrophobic spacers 10 b are close to each other,because a restraining force induced from the alignment film 6 thataligns the liquid crystal molecules of the liquid crystal layer 3 is notexerted on the surface of each spacer 10 b. Hence, the linear alignmentdefect region 15 having spacers as a nucleus as is shown in FIG. 6 doesnot occur between spacers due to an external force or stress, such asheat; however, leakage of light occurs from the periphery of thehydrophobic spacers 10 b with an increase of the density of thehydrophobic spacers 10 b.

Hence, in the invention, as will be described in Examples below, thespacer density of the hydrophobic spacers 10 b is optimized by takinginto account an alignment defect between spacers, leakage of light fromthe periphery of the spacers, uniformity of the panel GAP (thickness ofthe liquid crystal layer).

EXAMPLES Example 1

A semi-transmissive liquid crystal display device having a lightreflective region and a light transmissive region in one pixel andprovided with transparent spacers at a density of 200 pieces/mm² wasmanufactured. Also, a semi-transmissive liquid crystal display deviceprovided with black spacers at a density of 200 pieces/mm² wasmanufactured.

In addition, a semi-transmissive liquid crystal display device providedwith semi-transparent spacers at a density of 200 pieces/mm² wasmanufactured.

More specifically, the radius r was set, for example, to 3 μm for eachspacer.

TABLE 1 and TABLE 2 show evaluation results of roughness caused by whitedropouts in the black display and roughness caused by black spots in thewhite display for the value of πr²/S when NA−NB=1 was given in Equation(1) above.

TABLE 1 πr²/S 0.0010 0.0017 0.0023 0.0034 0.0047 0.0055 0.0067 0.0079TRANSPARENT ROUGHNESS IN WHITE DISPLAY ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ SPACERS ROUGHNESSIN BLACK DISPLAY ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ BLACK ROUGHNESS IN WHITE DISPLAY ◯ ◯ ◯◯ ◯ ◯ ◯ ◯ SPACERS ROUGHNESS IN BLACK DISPLAY ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ πr²/S0.0088 0.0101 0.0110 0.0117 0.0133 0.0150 0.0164 0.0207 TRANSPARENTROUGHNESS IN WHITE DISPLAY ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ SPACERS ROUGHNESS IN BLACKDISPLAY ◯ ◯ Δ Δ Δ Δ Δ Δ BLACK ROUGHNESS IN WHITE DISPLAY ◯ ◯ Δ Δ Δ Δ Δ ΔSPACERS ROUGHNESS IN BLACK DISPLAY ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ※ SPACER DENSITY: 200PIECES/mm²

TABLE 2 πr²/S 0.0010 0.0017 0.0023 0.0034 0.0047 0.0055 0.0067 0.0079SEMI-TRANSPARENT ROUGHNESS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ SPACERS WHITE DISPLAY(TRANSMITTANCE: 50%) ROUGHNESS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ BLACK DISPLAY πr²/S0.0088 0.0101 0.0110 0.0117 0.0133 0.0150 0.0164 0.0207 SEMI-TRANSPARENTROUGHNESS IN ◯ ◯ Δ Δ Δ Δ Δ Δ SPACERS WHITE DISPLAY (TRANSMITTANCE: 50%)ROUGHNESS IN ◯ ◯ Δ Δ Δ Δ Δ Δ BLACK DISPLAY ※ SPACER DENSITY: 200PIECES/mm²

For example, the value of πr²/S in TABLE 1 and TABLE 2 was varied byadjusting the size of the pixel and the area of the light transmissiveregion as set forth below.

-   -   (1) when πr²/S=0.0010: the dimension of one pixel excluding the        width of the light-shielding portion 20 (actually, equivalent to        the outside diameter dimension of the light reflective region R)        was set to 110 μm×350 μm, and the dimension of the light        transmissive region T in the reflection film 14 was set to 100        μm×269 μm, while the relation in terms of a ratio of the area of        the light reflective region to the area of the light        transmissive region in one pixel was set to 30:70.    -   (2) when πr²/S=0.0017: the outside diameter dimension of the        light reflective region R was set to 90 μm×290 μm, and the        dimension of the light transmissive region T was set to 80        μm×212 μm, while the relation in terms of a ratio of the area of        the light reflective region to the area of the light        transmissive region was set to 35:65.    -   (3) when πr²/S=0.0023: the outside diameter dimension of the        light reflective region R was set to 70 μm×230 μm, and the        dimension of the light transmissive region T was set to 60        μm×201 μm, while the relation in terms of a ratio of the area of        the light reflective region to the area of the light        transmissive region was set to 25:75.    -   (4) when πr²/S=0.0034: the outside diameter dimension of the        light reflective region R was set to 80 μm×260 μm, and the        dimension of the light transmissive region T was set to 70        μm×119 μm, while the relation in terms of a ratio of the area of        the light reflective region to the area of the light        transmissive region was set to 60:40.    -   (5) when πr²/S=0.0047: the outside diameter dimension of the        light reflective region R was set to 60 μm×200 μm, and the        dimension of the light transmissive region T was set to 50        μm×120 μm, while the relation in terms of a ratio of the area of        the light reflective region to the area of the light        transmissive region was set to 50:50.    -   (6) when πr²/S=0.0055: the outside diameter dimension of the        light reflective region R was set to 50 μm×170 μm, and the        dimension of the light transmissive region T was set to 40        μm×128 am, while the relation in terms of a ratio of the area of        the light reflective region to the area of the light        transmissive region was set to 40:60.    -   (7) when πr²/S=0.0067: the outside diameter dimension of the        light reflective region R was set to 60 μm×200 μm, and the        dimension of the light transmissive region T was set to 50 μm×84        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 65:35.    -   (8) when πr²/S=0.0079: the outside diameter dimension of the        light reflective region R was set to 60 μm×200 μm, and the        dimension of the light transmissive region T was set to 50 μm×72        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 70:30.    -   (9) when πr²/S=0.0088: the outside diameter dimension of the        light reflective region R was set to 70 μm×230 μm, and the        dimension of the light transmissive region T was set to 60 μm×54        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 80:20.    -   (10) when πr²/S=0.0101: the outside diameter dimension of the        light reflective region R was set to 50 μm×170 μm, and the        dimension of the light transmissive region T was set to 40 μm×70        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 67:33.    -   (11) when πr²/S=0.0110: the outside diameter dimension of the        light reflective region R was set to 50 μm×170 I'm, and the        dimension of the light transmissive region T was set to 40 μm×64        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 33:67.    -   (12) when πr²/S=0.0117: the outside diameter dimension of the        light reflective region R was set to 60 μm×200 μm, and the        dimension of the light transmissive region T was set to 50 μm×48        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 80:20.    -   (13) when πr²/S=0.0133: the outside diameter dimension of the        light reflective region R was set to 50 μm×170 μm, and the        dimension of the light transmissive region T was set to 40 μm×53        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 75:25.    -   (14) when πr²/S=0.0150: the outside diameter dimension of the        light reflective region R was set to 50 μm×170 μm, and the        dimension of the light transmissive region T was set to 40 μm×47        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 78:22.    -   (15) when πr²/S=0.0164: the outside diameter dimension of the        light reflective region R was set to 50 μm×170 μm, and the        dimension of the light transmissive region T was set to 40 μm×43        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 80:20.    -   (16) when πr²/S=0.0207: the outside diameter dimension of the        light reflective region R was set to 50 μm×170 μm, and the        dimension of the light transmissive region T was set to 40 μm×34        μm, while the relation in terms of a ratio of the area of the        light reflective region to the area of the light transmissive        region was set to 84:16.

As is set forth in TABLE 1, with the transparent spacers, neitherroughness nor display irregularities are observed at all in the whitedisplay and the black display when πr²/S is in a range from 0.001 to0.01, whereas when πr²/S is larger than 0.01, although roughness is notobserved in the white display, roughness and display irregularities areobserved in the black display.

With the black spacers, when πr²/S is larger than 0.01, althoughroughness is not observed in the black display, roughness and displayirregularities are observed in the white display.

Also, as is shown in TABLE 2, when πr²/S is in a range from 0.001 to0.01, neither roughness nor display irregularities are observed at allin the white display and the black display, whereas when πr²/S is largerthan 0.01, roughness is observed in both the white display and the blackdisplay.

The reason why roughness and display irregularities in the white displayand roughness and display irregularities in the black display vary withthe value of πr²/S in this manner is because when πr²/S is large, asingle spacer has a large proportion to the light transmissive regionand roughness caused by the spacers is visually recognized more easily,which appears as the display irregularities, whereas when πr²/S issmall, a spacer has a small proportion to the light transmissive regionand roughness is not visually recognized easily.

TABLE 3 compares the transparent spacers with the black spacers in termsof roughness in the white display, roughness in the black display,uniformity of the panel GAP (thickness of the liquid crystal layer 16)when the spacer density is varied.

Herein, a 3.8-inch diagonal semi-transmissive, STN liquid crystaldisplay device was used. The outer diameter dimension of the lighttransmissive region R was 70 μm×230 μm, and the number of pixels was 240RGB×320 dots. The dimension of the light transmissive region T was 50μm×96.6 μm, and a ratio of the area of the light reflective region tothe area of the light transmissive region was 70:30.

TABLE 3 SPACER DENSITY (PIECES/mm²) 30 40 50 60 70 80 90 100 110 120 130140 150 160 170 180 190 200 TRANSPARENT ROUGHNESS ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ SPACERS IN WHITE DISPLAY ROUGHNESS ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ ◯ ◯Δ Δ X X X X IN BLACK DISPLAY PANEL GAP X X X X X Δ Δ Δ Δ Δ Δ ◯ ◯ ◯ ◯ ⊚ ⊚⊚ UNIFORMITY BLACK ROUGHNESS ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ ◯ ◯ Δ Δ X X X X SPACERSIN WHITE DISPLAY ROUGHNESS ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ IN BLACKDISPLAY PANEL GAP X X X X X Δ Δ Δ Δ Δ Δ ◯ ◯ ◯ ◯ ⊚ ⊚ ⊚ UNIFORMITY

TABLE 3 reveals that for both the transparent spacers and the blackspacers, the uniformity of the thickness of the liquid crystal layer 16(panel GAP uniformity) is reduced when the scattering density of spacersis reduced.

For the transparent spacers, no roughness occurs in the white display ona whole range of the spacer density, whereas the occurrence of roughnessin the black display is reduced as the spacer density is reduced.

For the black spacers, no roughness occurs in the black display on awhole range of the spacer density, whereas the occurrence of roughnessin the white display is reduced as the spacer density is reduced.

TABLE 4 compares roughness in the white display, roughness in the blackdisplay, and uniformity of the thickness of the liquid crystal layer 16(panel GAP uniformity) when a mixing ratio of the black spacers and thetransparent spacers was varied in the structure in which the blackspacers and the transparent spacers were mixed.

In order to keep the panel GAP uniformity, the spacer density was keptto be constant at 200 pieces/mm². The size of the light transmissiveregion T in the reflection film was 50 μm×96.6 μm, and a ratio of thearea of the light reflective region to the area of the lighttransmissive region was 70:30.

TABLE 4 TRANSPARENT SPACERS  0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%BLACK SPACERS 100% 90% 80% 70% 60% 50% 40% 30% 20% 10%  0% ROUGHNESS INWHITE DISPLAY X X Δ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ROUGHNESS IN BLACK DISPLAY ⊚ ⊚ ⊚ ⊚ ⊚⊚ ◯ ◯ Δ X X PANEL GAP UNIFORMITY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ※ 200 PIECES/mm²

TABLE 4 reveals that when a ratio of the number of the transparentspacers to the number of the black spacers is in a range from 0:100 to10:90, although no roughness is observed in the black display, roughnessin the white display is deteriorated.

In addition, when a ratio of the transparent spacers to the blackspacers is in a range from 90:10 to 100:0, although no roughness isobserved in the white display, roughness in the black display isdeteriorated.

When a ratio of the black spacers to the transparent spacers is in arange from 20:80 to 80:20, roughness in the white display and roughnessin the black display both tend to improve (a region marked with Δ orbetter in TABLE 4). A ratio of the black spacers to the transparentspacers is preferably in a range from 30:70 to 70:30 (a range markedwith ∘ or better in TABLE 4), and roughness is improved mostsatisfactorily when a ratio of the black spacers to the transparentspacers is 50:50 (a range marked with ⊚ in TABLE 4).

In view of the foregoing, in a semi-transmissive liquid crystal displaydevice having a light reflective region and a light transmissive regionwithin a single pixel and performing a liquid crystal display usingambient external light and light from the backlight, by providing theblack spacers and the transparent spacers at a mixing ratio in the rangefrom 20%:80% to 80%:20% in a space between two transparent substrates atthe top and bottom, it is possible to provide a liquid crystal displaydevice capable of maintaining uniformity of the GAP (interval) betweenthe two substrates and having no display irregularities, such asroughness, in both the black display and the white display.

TABLE 5 compares roughness in the white display, roughness in the blackdisplay, uniformity of the thickness of the liquid crystal layer (panelGAP uniformity) with respect to light transmittance of semi-transparentspacers.

In order to keep the panel GAP uniformity, the spacer density was set tobe constant at 200 pieces/mm². The size of the light transmissive regionT in the reflection film was 50 μm×96.6 μm, and a ratio of the area ofthe light reflective region to the area of the light transmissive regionwas 70:30.

TABLE 5 TRANSMITTANCE OF SEMI-TRANSPARENT SPACERS 0% 10% 20% 30% 40% 50%60% 70% 80% 90% 100% ROUGHNESS IN WHITE DISPLAY X X Δ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ROUGHNESS IN BLACK DISPLAY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ Δ X X PANEL GAP UNIFORMITY ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚

TABLE 5 reveals that when transmittance of the semi-transparent spacersis in a range from 0% to 10%, although no roughness is observed in theblack display, roughness in the white display is deteriorated.

Also, when transmittance of the semi-transparent spacers is in a rangefrom 90% to 100%, although no roughness is observed in the whitedisplay, roughness in the black display is deteriorated.

When transmittance of the semi-transparent spacers is in a range from20% to 80%, roughness in the white display and roughness in the blackdisplay both tend to improve (a range marked with Δ or better in TABLE5). Preferably, transmittance of the semi-transparent spacers is in arange from 30% to 70% (a range marked with ∘ or better in TABLE 5), androughness is improved most satisfactorily when transmittance is 50% (arange marked with ⊚ in TABLE 5).

In view of the foregoing, in a semi-transmissive liquid crystal displaydevice having a light reflective region and a light transmissive regionwithin a single pixel and performing a liquid crystal display usingambient external light and light from the backlight, by providingsemi-transparent spacers having transmittance in a range from 20% to 80%in a space between two transparent substrates at the top and bottom, itis possible to obtain a liquid crystal display device capable ofmaintaining the uniformity of the GAP (interval) between two substrates4 and 4 and having no display irregularities, such as roughness, in boththe black display and the white display.

Example 2

Visual recognition and an alignment defect of liquid crystal caused bypressing were checked in a liquid crystal display device using thespacers shown in FIG. 4.

The black base material particle 20 a and a transparent base materialparticle as a comparative example were prepared as base materialparticles of the spacers. Further, for the base material particles ofeach type, those with and without the hydrophilic group film 20 b wereprepared.

Further, those with and without the alkyl group film 20 c were prepared.Furthermore, for those having the alkyl group film 20 c, the thickness(maximum number of carbons) of the alkyl groups was varied in variousmanners.

TABLE 6 shows the result when roughness caused by white dropouts in theblack display, roughness caused by black spots in the white display, andan alignment defect of liquid crystal caused by pressing were checked inthe liquid crystal device using the spacers.

TABLE 6 SPACER BASE MATERIAL TRANSPARENT MAXIMUM NUMBER OF CARBONS OFALKYL GROUP NAUGHT NAUGHT 8 10 12 14 HYDROPHILIC GROUP WITHOUT WITH WITHWITH WITH WITH WHITE DROPOUTS IN BLACK DISPLAY X X X X Δ Δ Δ BLACK SPOTSIN WHITE DISPLAY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ALIGNMENT DEFECT CAUSED BY PRESSING ◯ ◯ X ◯◯ ◯ SPACER BASE MATERIAL BLACK MAXIMUM NUMBER OF CARBONS OF ALKYL GROUPNAUGHT NAUGHT 8 10 11 12 13 14 HYDROPHILIC GROUP WITHOUT WITH WITH WITHWITH WITH WITH WITH WHITE DROPOUTS IN BLACK DISPLAY Δ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚BLACK SPOTS IN WHITE DISPLAY ◯ ◯ ◯ ◯ ◯ ◯ ◯ X ALIGNMENT DEFECT CAUSED BYPRESSING ◯ ◯ X X ◯ ◯ ◯ ◯

TABLE 6 reveals that when the base material particle is the transparentbase material, it is quite difficult to eliminate white dropouts in theblack display by increasing the maximum number of carbons of the alkylgroup.

Meanwhile, when the base material of the spacers is the black basematerial particle 20 a, white dropouts in the black display are notsatisfactory in the complete absence of the substitutional group film 20b having a hydrophilic property and the alkyl group film 20 c.

When the base material of the spacers is the black base materialparticle 20 a, white dropouts in the black display are satisfactory inthe presence of the substitutional group film 20 b having a hydrophilicproperty. Further, white dropouts in the black display are extremelysatisfactory in the presence of the alkyl group film 20 c.

Also, in a case where the substitutional group film 20 b having ahydrophilic property as well as the alkyl group film 20 c are formed onthe surface of the black base material particle 20 a, when an alignmentrestraining force on liquid crystal molecules of the liquid crystal 16is increased by increasing the maximum number of carbons to 14 or more,the spacer aligns the liquid crystal molecules in a broad range on theperiphery of the spacer in the white display, which conversely givesrise to black spots that appear noticeably as irregularities in thewhite display, and the liquid crystal display device goes into a uselessstate (marked with x in TABLE 6).

In a case where the substitutional group film 20 b having a hydrophilicproperty as well as the alkyl group film 20 c are formed on the surfaceof the black base material particle 20 a, when the maximum number ofcarbons of the alkyl group film 20 c is 10 or less, an alignmentrestraining force on liquid crystal molecules becomes so weak that analignment defect occurs when an external force is applied to the liquidcrystal display device, and the liquid crystal display goes into auseless state (marked with x in TABLE 6).

In a case where the alkyl group film itself is not formed, because thehydrophilic group also has an alignment restraining force on the liquidcrystal molecules, white dropouts in the black display are more likelyto occur (marked with Δ in TABLE 6).

As has been described, TABLE 6 reveals a tendency that overall visualrecognition is increased either in the black display or in the whitedisplay when the liquid crystal panel DP performing the display in thereflective mode and the display in the transmissive mode is activated,by using the black base material particle 20 a than by using thetransparent base material particles. It is thus possible to provide aliquid crystal display device extremely suitable for a practical use.

The film thickness of the hydrophilic group film 20 b formed on thesurface of the black base material particle 20 a will now be described.

The spacers 10 are scattered, for example, by means of wet scattering onone of the glass substrates chiefly in fabrication sequence. It isimportant that the spacers 10 are scattered uniformly in the displayregion as a result of scattering. In order to improve visual recognitionof the liquid crystal display, aggregation of the spacers 10 should beavoided.

TABLE 7 shows the evaluation result of a scattering property at the timeof wet scattering by varying the film thickness of the hydrophilic groupfilm 20 b of the spacer 10.

TABLE 7 FILM THICKNESS OF 0.01 μm 0.02 μm 0.03 μm 0.04 μm 0.05 μm 0.06μm 0.07 μm 0.08 μm 0.09 μm 0.10 μm 0.15 μm HYDROPHILIC GROUP SCATTERINGPROPERTY X ◯ ◯ ◯ ◯ ◯ X X X X X AT WET SCATTERING

A scattering solution was manufactured by mixing 500 g of IPA (isopropylalcohol) and 500 g of pure water with 10 g of spacers provided with thehydrophilic group film 20 b having a specific film thickness. Thespacers 10 were scattered by spraying the scattering solution to thesubstrate from 1.5 to 2.0 m above, and evaluation was made as to theoccurrence of aggregation and the like.

In a case where the hydrophilic group film was formed on the surface ofthe spacer in film thicknesses up to 0.01 μm and in a range from 0.07 to0.15 μm, as is revealed in TABLE 7, aggregation occurred as a result ofwet scattering.

On the contrary, when the film thickness of the hydrophilic group film20 b on the surface of the spacer 10 was set to 0.02 to 0.06 μm, noaggregation occurred as a result of wet scattering, and the scatteringproperty was satisfactory.

As has been described, a hydrophilic property varies with the thicknessof the hydrophilic group film 20 b. When the hydrophilic property is toosmall, the spacers 10 are not scattered uniformly in pure watercontaining alcohol, which gives rise to aggregation. When thehydrophilic property is too large, the spacers 10 move too freely inpure water containing alcohol, and aggregation is thought to occurbecause the spacers 10 try to assemble in the solution. Either case ismarked with x in TABLE 7.

The shape of the spacer 10, more specifically, the area when viewed in aplane, an adequate range of the light transmissive region T, and therelation with the alkyl group film, were checked.

As with the other examples, the radius of the spacer, r, was set to r=3μm. Also, S is given as the dimension of the light transmissive regionT.

TABLE 8 shows the evaluation result of white dropouts in the blackdisplay, black spots in the white display, an alignment defect caused bypressing by varying the value of πr²/S when NA−NB=1 (0 is ideal) wasgiven in Equation (1) above and the film thickness (length of alkylgroups) of the alkyl group film formed on the outermost surface of thespacer. All the spacers used herein were the spacers made of the blackbase material particles.

TABLE 8 MAXIMUM NUMBER OF HYDRO- CARBONS OF PHILIC πr²/S ALKYL GROUPGROUP PARTICULARS 0.0010 0.0017 0.0023 0.0034 0.0047 0.0055 0.00670.0079 NAUGHT WITH- WHITE DROPOUTS IN Δ Δ Δ Δ Δ Δ Δ Δ OUT BLACK DISPLAYBLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAY ALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯◯ ◯ ◯ CAUSED BY PRESSING NAUGHT WITH WHITE DROPOUTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAY ALIGNMENTDEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 1 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAYALIGNMENT DEFECT X X X X X X X X CAUSED BY PRESSING 2 WITH WHITEDROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X X CAUSED BY PRESSING 8 WITHWHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯◯ ◯ ◯ WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X X CAUSED BY PRESSING9 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X X CAUSED BYPRESSING 10 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACKSPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X XCAUSED BY PRESSING 11 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACKDISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAY ALIGNMENT DEFECT ◯◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 12 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAY ALIGNMENTDEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 13 WITH WHITE DROPOUTS IN ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAYALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 14 WITH WHITEDROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN Δ Δ Δ Δ Δ Δ Δ XWHITE DISPLAY ALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 15WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN Δ ΔΔ Δ X X X X WHITE DISPLAY ALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BYPRESSING MAXIMUM NUMBER OF HYDRO- CARBONS OF PHILIC πr²/S ALKYL GROUPGROUP PARTICULARS 0.0088 0.0101 0.0110 0.0117 0.0133 0.0150 0.01640.0207 NAUGHT WITH- WHITE DROPOUTS IN Δ Δ Δ Δ Δ Δ Δ Δ OUT BLACK DISPLAYBLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAY ALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯◯ ◯ ◯ CAUSED BY PRESSING NAUGHT WITH WHITE DROPOUTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯BLACK DISPLAY BLACK SPOTS IN ◯ ◯ Δ Δ Δ Δ Δ Δ WHITE DISPLAY ALIGNMENTDEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 1 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ WHITE DISPLAYALIGNMENT DEFECT X X X X X X X X CAUSED BY PRESSING 2 WITH WHITEDROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X X CAUSED BY PRESSING 8 WITHWHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ ◯◯ ◯ ◯ WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X X CAUSED BY PRESSING9 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯◯ ◯ ◯ ◯ ◯ ◯ Δ WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X X CAUSED BYPRESSING 10 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACKSPOTS IN ◯ ◯ ◯ ◯ ◯ ◯ Δ Δ WHITE DISPLAY ALIGNMENT DEFECT X X X X X X X XCAUSED BY PRESSING 11 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACKDISPLAY BLACK SPOTS IN ◯ ◯ ◯ ◯ Δ Δ Δ Δ WHITE DISPLAY ALIGNMENT DEFECT ◯◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 12 WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ ◯ Δ Δ Δ Δ Δ WHITE DISPLAY ALIGNMENTDEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 13 WITH WHITE DROPOUTS IN ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN ◯ ◯ Δ Δ Δ Δ Δ Δ WHITE DISPLAYALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 14 WITH WHITEDROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN X X X X X X X XWHITE DISPLAY ALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BY PRESSING 15WITH WHITE DROPOUTS IN ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ BLACK DISPLAY BLACK SPOTS IN X XX X X X X X WHITE DISPLAY ALIGNMENT DEFECT ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ CAUSED BYPRESSING

Referring to TABLE 8, the value of πr²/S is varied from 0.0010 to0.0207, and because the contents are the same as those described withreference to TABLE 1 and TABLE 2 above, the descriptions are notrepeated herein.

TABLE 8 reveals that let r be a radius of the black base materialparticle, and S be the dimension of the light transmissive region T onthe pixel region, then it is preferable to set the value of πr²/S to0.001 to 0.01 when the spacer comprises the black base material particle20 a and the hydrophilic group film 20 b deposited on the surface of theparticle.

In addition, when the alkyl group film 20 c is provided on the surfaceof the hydrophilic group film 20 b, it is particularly important to setthe maximum number of carbons to 11 to 13.

On the whole range where πr²/S=0.01 or less, white dropouts in the blackdisplay are satisfactory; moreover, display of black spots in the whitedisplay is markedly improved.

In a case where the maximum number of carbons of the alkyl group is 15,a few black spots are observed in the white display when πr²/S is in arange from 0.001 to 0.034.

In a case where the maximum number of carbons of the alkyl group is 14,a few black spots are observed in the white display when πr²/S is in arange from 0.001 to 0.0067.

In a case where the maximum number of carbons of the alkyl group is 13,no black spots are observed in the white display when πr²/S is in arange from 0.001 to 0.0101.

In a case where the maximum number of carbons of the alkyl group is 12,no black spots are observed in the white display when πr²/S is in arange from 0.001 to 0.0110.

In a case where the maximum number of carbons of the alkyl group is 11,no black spots are observed in the white display when πr²/S is in arange from 0.001 to 0.0117.

In a case where the maximum number of carbons of the alkyl group is in arange from 1 to 10, an alignment defect caused by pressing is observedon a whole range of πr²/S.

As has been described, the maximum number of carbons of the alkyl groupis preferably in a range from 11 to 13 in preventing the occurrence ofblack spots in the white display in accordance with the value of πr²/S.

The reason why is because, in the white display, liquid crystalmolecules are in a state where they stand perpendicularly with respectto the top and bottom substrates, whereas liquid crystal molecules ofthe liquid crystal 16 on the periphery of the spacer are horizontal withrespect to the top and bottom substrates 4 a and 4 b, which causes theperiphery of the spacer to appear in black.

The length of the alkyl chain formed on the periphery of the spacerbecomes longer as the maximum number of carbons of the alkyl groupformed on the periphery of the spacer is increased, and an alignmentrestraining force to align the liquid crystal 16 perpendicularly to thespacer becomes stronger.

For example, when the maximum number of carbons of the alkyl group isset to 14 or larger, liquid crystal molecules of the liquid crystal 16on a broader periphery of the spacer are aligned perpendicularly, whichblackens a broader periphery of the spacer.

In addition, when πr²/S is small, because the spacer has a smallproportion to the light transmissive region T, even when a black regionon the periphery of the spacer becomes larger, the influence is little.

On the contrary, when a dimension ratio of the light transmissive regionT is small, because the spacer has a large proportion to the lighttransmissive region, when a black region on the periphery of the spacerbecomes larger, it is visually recognized with ease.

Hence, even when the maximum number of carbons of the alkyl group isincreased, black spots in the white display occur less readily as thedimension of the light transmissive region T is smaller. When the areaof the light transmissive region is increased, black spots occur in thewhite display where the maximum number of carbons of the alkyl group issmall.

When the maximum number of carbons of the alkyl group forming the alkylgroup film 20 c is set to 10 or smaller, an alignment defect caused bypressing occurs in the liquid crystal display device on a whole range ofπr²/S because an alignment restraining force on liquid crystal moleculesof the liquid crystal 16 is weak.

Further, in a case where an alkyl group per se is not formed, whitedropouts in the black display can be eliminated and no alignment defectoccurs when an external force is applied on a whole range of πr²/S,because a hydrophilic group also has an alignment restraining force onliquid crystal molecules.

In view of the foregoing, as conditions to satisfy all the evaluationson white dropouts in the black display, black spots in the whitedisplay, and an alignment defect caused by pressing in a liquid crystaldisplay device in which the reflection film 9 provided with lighttransmissive regions is formed on the substrate 4 b on the lower side,by providing spacers, formed by forming the hydrophilic group film 20 band the alkyl group film 20 c having alkyl groups up to 11 to 13 carbonson the surface of the black base-material particle 20 a, in the liquidcrystal 16 while setting πr²/S to a range from 0.001 to 0.01 bothinclusive, or by providing spacers having the hydrophilic groups aloneon the black base material particle, it is possible to provide a liquidcrystal display device having no display irregularities.

Example 3

TABLE 9 shows the result when the spacer density of the hydrophobicspacers 10 b, an alignment defect between spacers, leakage of light fromthe periphery of spacers, uniformity of the panel GAP (thickness of theliquid crystal layer) were checked.

TABLE 9 HYDROPHOBIC TREATMENT SPACER DENSITY (PIECES/mm²) 20 40 60 80100 120 140 160 180 200 ALIGNMENT DEFECT BETWEEN SPACERS ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚⊚ ⊚ LEAKAGE OF LIGHT FROM PERIPHERY OF SPACER ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ ◯ Δ X PANELGAP UNIFORMITY X X X Δ Δ Δ Δ ◯ ◯ ⊚

An alignment defect between the hydrophobic spacers 10 b is satisfactorywhen the hydrophobic spacer density is in a range from 20 to 200pieces/mm². This is because no alignment restraining force on liquidcrystal molecules is exerted on the spacer surface, and no alignmentdefect occurs between the spacers where spacers are close to each other.

Leakage of light from the periphery of spacers is satisfactory when thehydrophobic spacer density is in a range from 20 to 100 pieces/mm²;however, it deteriorates as the density of the hydrophobic spacers 10 bincreases.

The is because liquid crystal molecules are aligned horizontally alongthe surface of the hydrophobic spacers 10 b and leakage of light occurson the peripheral portion of all the hydrophobic spacers 10 b. When ascattering density of the hydrophobic spacers 10 b in the liquid crystallayer 3 is increased, a light leaking portion, when viewed from thedisplay surface side, becomes noticeable.

The panel GAP uniformity (uniformity of the layer thickness of theliquid crystal layer 3 in the pixel region) is satisfactory when thedensity of the hydrophobic spacers 10 b is at 200 pieces/mm²; however,it deteriorates as the hydrophobic spacer density is reduced. Forexample, at lower than 80 pieces/mm², it is far below a display levelfor a practical use (marked with x in the table), in a range from 80pieces/mm² inclusive to 160 pieces/mm² exclusive, it is below a displaylevel for a practical use (marked with Δ in the table), in a range from160 pieces/mm² inclusive to 200/mm² exclusive, it reaches a displaylevel for a practical use (marked with ∘ in the table), and at 200pieces/mm² or above, it reaches a satisfactory display level because theuniformity of the thickness of the liquid crystal layer can be achievedin a stable manner (marked with ⊚ in the table). This is because spacer3 functions as a pillar that supports the two transparent substrates 4and 4.

A spacer density, an alignment defect between spacers, leakage of lightfrom the periphery of spacers, and the panel GAP uniformity were checkedin a case where the hydrophilic spacers 10 a alone were used. The resultis set forth in TABLE 10.

TABLE 10 HYDROPHILIC TREATMENT SPACER DENSITY (PIECES/mm²) 20 40 60 80100 120 140 160 180 200 ALIGNMENT DEFECT BETWEEN SPACERS ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ ◯Δ Δ LEAKAGE OF LIGHT FROM PERIPHERY OF SPACER ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ PANELGAP UNIFORMITY X X X Δ Δ Δ Δ ◯ ◯ ⊚

An alignment defect between spacers achieves a satisfactory displaylevel when the spacer density of the hydrophilic spacers 10 a is in arange from 20 pieces/mm² inclusive to 120 pieces/mm² exclusive (markedwith ⊚ in the table), and it deteriorates as a distribution density ofthe hydrophilic spacers 10 a is increased. For example, in a range from120 pieces/mm² inclusive to 180 pieces/mm² exclusive, it reaches adisplay level for a practical use (marked with ∘ in the table), and at180 pieces/mm² or above, it is below a display level for a practical use(marked with Δ in the table)

The reason why is because a strong alignment restraining force on liquidcrystal molecules is exerted on the surface of the spacer a, analignment defect occurs between the hydrophilic spacers 10 a in aportion where the spacers 10 a are close to each other. The frequency ofsuch occurrences increases as the density of the hydrophilic spacers 10a increases.

Leakage of light from the periphery of spacers is satisfactory when ahydrophilic spacer density is in a range from 20 to 200 pieces/mm².

This is because an alignment restraining force on liquid crystalmolecules is exerted on the surface of the hydrophilic spacer 10 a,leakage of light does not occur on the periphery of all the hydrophilicspacers.

As with the hydrophobic spacers 10 b, the panel GAP uniformity(uniformity of the layer thickness of the liquid crystal layer in thepixel region) is satisfactory when a density of spacers is at 200pieces/mm²; however, it deteriorates as a density of the hydrophilicspacers 10 a is reduced.

Hence, an overall density of the hydrophilic spacers 10 a and thehydrophobic spacers 10 b was set to 200 pieces/mm² by taking intoaccount the uniformity of the layer thickness of the liquid crystallayer, and the hydrophilic spacers 10 a and the hydrophobic spacers 10 bwere mixed in order to eliminate leakage of light from the periphery ofspacers, which is a problem of the hydrophobic spacers 10 b, and analignment defect 15 between spacers, which is a problem of thehydrophilic spacers 10 a.

An alignment defect 15 between spacers, leakage of light from theperiphery of spacers, and a panel GAP uniformity were checked atspecific mixing ratios.

The result is set forth in TABLE 11. A density of the spacers 10 a and10 b was set to 200 pieces/mm². The purpose was to stabilize the panelGAP uniformity.

TABLE 11 HYDROPHILIC TREATMENT SPACERS  0% 10% 20% 30% 40% 50% 60% 70%80% 90% 100% HYDROPHOBIC TREATMENT SPACERS 100% 90% 80% 70% 60% 50% 40%30% 20% 10%  0% ALIGNMENT DEFECT BETWEEN SPACERS ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ ◯ Δ ΔLEAKAGE OF LIGHT FROM PERIPHERY OF SPACER X Δ ◯ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ PANELGAP UNIFORMITY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ※ SPACER DENSITY: 200 PIECES/mm²

An alignment defect between spacers is satisfactory when a mixing ratioof the hydrophilic spacers 10 a and the hydrophobic spacers 10 b is setso that a ratio of the hydrophilic spacers to the hydrophobic spacers isin a range from 0:100 to 50:50. A defective alignment 15 between spacers10 a and 10 a becomes noticeable as a mixing ratio of the hydrophilicspacers 10 a is increased further while a mixing ratio of thehydrophobic spacer 10 b is reduced.

To be more concrete, when the hydrophilic spacers 10 a account for 0 to80% of all the spacers, it reaches a satisfactory display level or adisplay level needed for a practical use. Preferably, when thehydrophilic spacers 10 a account for 0 to 50% of all the spacers, itreaches a satisfactory display level.

Leakage of light from the periphery of spacers is satisfactory when amixing ratio of the hydrophilic spacers 10 a and the hydrophobic spacers10 b is set so that a ratio of the hydrophilic spacers to thehydrophobic spacers is in a range from 100:0 to 50:50. It deteriorateswhen a mixing ratio of the hydrophilic spacers 10 a is reduced while amixing ratio of the hydrophobic spacers 10 b is increased.

To be more concrete, when the hydrophobic spacers 10 b account for morethan 80% of all the spacers, it reaches too poor a display level for apractical use. Preferably, when the hydrophobic spacers 10 b account for0 to 50% of all the spacers, it reaches a satisfactory display level.

Because an overall density of the hydrophilic spacers 10 a and thehydrophobic spacers 10 b is set to be constant at 200 pieces/mm², thepanel GAP uniformity is satisfactory on a whole range of a mixing ratioof the hydrophilic spacers 10 a and the hydrophobic spacers 10 b, thatis, when a ratio of the hydrophilic spacers to the hydrophobic spacersis in a range from 0:100 to 100:0.

In view of the foregoing, an alignment defect between spacers, leakageof light from the periphery of spacers, the panel GAP uniformity are allsatisfactory when a mixing ratio of the hydrophilic spacers 10 a and thehydrophobic spacers 10 b is set so that a ratio of the hydrophilicspacers to the hydrophobic spacers is in a range from 20:80 to 80:20.Preferably, the most satisfactory display level can be achieved when amixing ratio of the hydrophilic spacers 10 a with respect to all thespacers exceeds 40% and is less than 60%, and a mixing ratio of thehydrophobic spacers 10 b with respect to all the spacers is less than60% and exceeds 40%.

TABLE 12 compares roughness in the white display, roughness in the blackdisplay, an alignment defect between spacers, and the panel GAPuniformity when the hydrophilic spacers 10 a and the hydrophobic spacers10 b were mixed so that each accounts for 50%, and substantiallytransparent spacers and substantially black spacers were mixed.

TABLE 12 RATIO OF TRANSPARENT SPACERS  0% 10% 20% 30% 40% 50% 60% 70%80% 90% 100% RATIO OF BLACK SPACERS 100% 90% 80% 70% 60% 50% 40% 30% 20%10%  0% ROUGHNESS IN WHITE DISPLAY X Δ ◯ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ROUGHNESS INBLACK DISPLAY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ ◯ Δ X ALIGNMENT DEFECT BETWEEN SPACERS ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ PANEL GAP UNIFORMITY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ※ SPACERDENSITY: 200 PIECES/mm²

A base material of transparent spacers is formed by subjecting a monomerhaving unsaturated ethylene groups to suspension polymerization using aradical polymerizing agent. When transparent hydrophilic spacers areformed, they are formed by applying the alkyl treatment as describedabove.

Black spacers are obtained by mixing a black pigment with the monomer,or covering the periphery of the transparent base material with a blackcoating film. When black hydrophilic spacers are to be formed, they areformed by applying the alkyl treatment as described above.

When a mixing ratio of the transparent spacers and the black spacers isset so that a ratio of the transparent spacers to the black spacers isin a range from 0:100 to 10:90, no roughness is observed in the blackdisplay; however, roughness in the white display is deteriorated. When aratio of the transparent spacers to the black spacers is in a range from90:10 to 100:0, no roughness is observed in the white display; however,roughness in the black display is deteriorated.

When a ratio of the transparent spacers to the black spacers is in arange from 20:80 to 80:20, roughness in the white display and roughnessin the black display both tend to improve. When a ratio of thetransparent spacers to the black spacers is 50:50, roughness is improvedmost satisfactorily.

In view of the foregoing, it is possible to obtain a liquid crystaldisplay device in which no alignment defect occurs between spaces androughness in the white display and roughness in the black display areboth satisfactory.

TABLE 13 compares roughness in the white display, roughness in the blackdisplay, an alignment defect between spacers, and the panel GAPuniformity when hydrophilic spacers and hydrophobic spacers were mixedat a ratio of 50%:50% and semi-transparent spacers were used.

TABLE 13 TRANSMITTANCE OF SEMI-TRANSPARENT SPACERS 0% 10% 20% 30% 40%50% 60% 70% 80% 90% 100% ROUGHNESS IN WHITE DISPLAY X Δ ◯ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚⊚ ROUGHNESS IN BLACK DISPLAY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ◯ ◯ Δ X ALIGNMENT DEFECTBETWEEN SPACERS ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ PANEL GAP UNIFORMITY ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚⊚ ⊚ ⊚ ⊚ ※ SPACER DENSITY: 200 PIECES/mm²

Semi-transmissive spacers are obtained by mixing a small quantity of ablack pigment with a monomer having unsaturated ethylene groups, or bycovering the periphery of a transparent base material slightly with ablack coating film.

When transmittance of the semi-transparent spacers is in a range from 0%to 10%, no roughness is observed in the black display; however,roughness in the white display is deteriorated.

When transmittance of the semi-transparent spacers is in a range from90% to 100%, no roughness is observed in the white display; however,roughness in the black display is deteriorated.

When transmittance of the semi-transparent spacers is in a range from20% to 80%, roughness in the white display and roughness in the blackdisplay both tend to improve, and both are improved most satisfactorilywhen transmittance of semi-transparent spacers is 50%.

In view of the foregoing, it is possible to obtain a liquid crystaldisplay device in which no alignment defect occurs between spacers androughness in the white display and roughness in the black display areboth satisfactory.

By forming a display body provided at least with the liquid crystaldisplay panel DP having the spacers as described above and the backlightBL that are accommodated in a case container, and a driving circuit thatprovides a specific signal to the transparent electrodes 5 (or switchingtransistors), a satisfactory liquid crystal display having no alignmentdefect, no roughness in the white display, and no roughness in the blackdisplay is enabled.

While embodiments of the invention have been described, the invention isnot limited to the embodiments above.

For example, the color filter 8 may be formed on the display substrate 4a side.

Also, the transparent electrodes 5 b formed on the transparent substrate4 b may be formed in the form of a single transparent conducting filmspread across plural pixel regions, so that the transparent electrodes 5a on the transparent substrate 4 a having no color filter 8 are formedin a matrix fashion to correspond to respective pixel regions, andswitching transistor elements are connected to the respectivetransparent electrodes 5 a thus formed. In short, an active liquidcrystal panel DP of a TFT type, a TFD type or the like can be used aswell.

1. A liquid crystal display device provided with a liquid crystal panelhaving plural pixel regions arrayed in a matrix fashion comprising: afirst substrate on a display surface side, provided with a transparentconducting film and an alignment film; a second substrate disposedoppositely to the first substrate on a back surface side and providedwith a transparent conducting film and an alignment film; a liquidcrystal layer in a space between the two substrates; a reflection filmprovided on the second substrate; plural spacers in the space; and abacklight that supplies light to the pixel regions via the secondsubstrate, wherein the reflection film has a light reflective region anda light transmissive region provided with a light transmission hole foreach pixel region, and light transmittance of the plural spacersprovided in the light transmissive region is in a range from 20 to 80%,wherein the spacers include black spacers and transparent spacers, and amixing ratio of the black spacers and the transparent spacers is set ina range from 20:80 to 80:20.
 2. The liquid crystal display deviceaccording to claim 1, wherein the spacers further includesemi-transparent spacers.
 3. The liquid crystal display device accordingto claim 1, wherein part of or all the black spacers are spacerssubjected to hydrophilic treatment, each being made of a black basematerial particle and a hydrophilic group film deposited on a surface ofthe particle.
 4. The liquid crystal display device according to claim 3,wherein an alkyl group film having up to 11 to 13 carbons is formed anddeposited on a surface of the hydrophilic group film.
 5. The A liquidcrystal display panel having plural pixel regions arrayed in a matrixfashion comprising: a first substrate on a display surface side,provided with a transparent conducting film and an alignment film; asecond substrate disposed oppositely to the first substrate on a backsurface side and provided with a transparent conducting film and analignment film; a liquid crystal layer in a space between the twosubstrates; a reflection film provided on the second substrate; andplural spacers in the space; wherein the reflection film has a lightreflective region and a light transmissive region provided with a lighttransmission hole for each pixel region, the spacers comprise firstspacers and second spacers both in the light transmissive region, thefirst and the second spacers having different light transmittance, andlet r be a radius of the spacers and S be an area of the lighttransmissive region, and then πr²/S is set in a range from 0.001 to0.01, wherein the first spacers are black spacers and the second spacersare transparent spacers, and a mixing ratio of the black spacers and thetransparent spacers is set in a range from 20:80 to 80:20.
 6. A liquidcrystal display device provided with a liquid crystal panel havingplural pixel regions arrayed in a matrix fashion comprising: a firstsubstrate on a display surface side, provided with a transparentconducting film and an alignment film; a second substrate disposedoppositely to the first substrate on a back surface side and providedwith a transparent conducting film and an alignment film; a liquidcrystal layer in a space between the two substrates; a reflection filmprovided on the second substrate; plural spacers in the space; and abacklight that supplies light to the pixel regions via the secondsubstrate, wherein the reflection film has a light reflective region anda light transmissive region provided with a light transmission hole foreach pixel region, and let r be a radius of the spacers and S be an areaof the light transmissive region, and then πr²/S is set in a range from0.001 to 0.01, wherein the spacers include black spacers and transparentspacers, and a mixing ratio of the black spacers and the transparentspacers is set in a range from 20:80 to 80:20, wherein the spacersfurther include semi-transparent spacers.
 7. A liquid crystal displaydevice provided with a liquid crystal panel having plural pixel regionsarrayed in a matrix fashion comprising: a first substrate on a displaysurface side, provided with a transparent conducting film and analignment film; a second substrate disposed oppositely to the firstsubstrate on a back surface side and provided with a transparentconducting film and an alignment film; a liquid crystal layer in a spacebetween the two substrates; a reflection film provided on the secondsubstrate; plural spacers in the space; and a backlight that supplieslight to the pixel regions via the second substrate, wherein thereflection film has a light reflective region and a light transmissiveregion provided with a light transmission hole for each pixel region,and let r be a radius of the spacers and S be an area of the lighttransmissive region, and then πr²/S is set in a range from 0.001 to0.01, wherein the spacers include black spacers and transparent spacers,and a mixing ratio of the black spacers and the transparent spacers isset in a range from 20:80 to 80:20, wherein part of or all the blackspacers are spacers subjected to hydrophilic treatment, each being madeof a black base material particle and a hydrophilic group film depositedon a surface of the particle.
 8. The liquid crystal display deviceaccording to claim 7, wherein an alkyl group film having up to 11 to 13carbons is formed and deposited on a surface of the hydrophilic groupfilm.
 9. The A liquid crystal display panel having plural pixel regionsarrayed in a matrix fashion comprising: a first substrate on a displaysurface side, provided with a transparent conducting film and analignment film; a second substrate disposed oppositely to the firstsubstrate on a back surface side and provided with a transparentconducting film and an alignment film; a liquid crystal layer in a spacebetween the two substrates; a reflection film provided on the secondsubstrate; and plural spacers in the space; wherein the reflection filmhas a light reflective region and a light transmissive region providedwith a light transmission hole for each pixel region, lighttransmittance of the plural spacers provided in the light transmissiveregion is in a range from 20 to 80%, and the spacers comprise firstspacers and second spacers both in the light transmissive region, thefirst and the second spacers having different light transmittance,wherein the first and the second spacers are different in color, whereinthe first spacers are black spacers and the second spacers aretransparent spacers.
 10. A liquid crystal display panel having pluralpixel regions arrayed in a matrix fashion comprising: a first substrateon a display surface side, provided with a transparent conducting filmand an alignment film; a second substrate disposed oppositely to thefirst substrate on a back surface side and provided with a transparentconducting film and an alignment film; a liquid crystal layer in a spacebetween the two substrates; a reflection film provided on the secondsubstrate; and plural spacers in the space; wherein the reflection filmhas a light reflective region and a light transmissive region providedwith a light transmission hole for each pixel region, the spacerscomprise first spacers and second spacers both in the light transmissiveregion, the first and the second spacers having different lighttransmittance, and let r be a radius of the spacers and S be an area ofthe light transmissive region, and then πr²/S is set in a range from0.001 to 0.01, wherein the first and the second spacers are different incolor, wherein the first spacers are black spacers and the secondspacers are transparent spacers.